Scientists grow a
'person on a chip' - living human tissues on a mini 3D structure
This could be the future of drug testing.
Scientists in Canada have developed a new
method of growing human tissue outside the body, creating a miniature lattice
structure that's capable of providing an external matrix for living cells.
Called AngioChip, the researchers say their
'person on a chip' technology could be a new platform for testing the effects
of drugs on human tissue, with the mini 3D scaffold constituting a more
realistic environment for growing cells than the flat layout of a petri dish.
"It's a fully three-dimensional structure
complete with internal blood vessels,"said chemical engineer Milica Radisic from
the University of Toronto. "It behaves just like vasculature, and around it there is a lattice for other
cells to attach and grow."
Built from a biodegradable and biocompatible
polymer called POMaC, the miniature scaffold is constructed
from a series of thin layers that resemble microchips, each indented with a
pattern of tiny channels measuring between 50 to 100 micrometres wide (about
the same diameter as a human hair).
Once stacked and bonded together via UV light,
these layers become a 3D structure of synthetic blood vessels. The lattice
network is then bathed in a liquid containing living cells. The cells attach to
the structure, and begin growing inside and outside of the tiny channels
stamped in the polymer.
"Previously, people could only do this
using devices that squish the cells between sheets of silicone and glass," said Radisic. "You needed several pumps
and vacuum lines to run just one chip. Our system runs in a normal cell culture
dish, and there are no pumps; we use pressure heads to perfuse media through
the vasculature. The wells are open, so you can easily access the tissue."
Tyler Irving / Boyang Zhang / Kevin Soobrian
The engineers have so far used AngioChip to
build small-scale living models of heart and liver tissues that function just
like real organs. "Our liver actually produced urea and metabolised
drugs," said Radisic.
What's more, connecting the blood vessels of
two different artificial organs on AngioChips lets the researchers study the
interactions between them, providing a testbed at the organ level.
Such testing could more accurately detect
dangerous side effects of potential or existing medications, or safely study
related interactions between various human organ compartments.
"In the last few years, it has become
possible to order cultures of human cells for testing, but they're grown on a
plate, a two-dimensional environment," said Radisic. "They don't capture all the
functional hallmarks of a real heart muscle, for example."
The researchers' technology is reported in Nature Materials.
They are now seeking to commercialise the system, which could end up having
applications even beyond drug testing. They say it's possible the artificial
AngioChip organs could be grown into tissues for directly implanting into
patients' bodies to repair damaged organs.
So far, the researchers have only tested this
application in rats, but the advantage of the system is that the polymer
scaffold is itself biodegradable, so after time it safely dissipates within the
subject's body, leaving only the newly grown tissue.
It sounds like it'll be a while before we see this kind of
technique used for human patients, but even so, we can't wait to see where this
research might lead.